Situation
Breast cancer is the most common malignant disease in women. Rarely, however, the primary tumor is the cause of death. The real threat is, that metastases form in important organs and impair their function. Circulating epithelial tumor cells (CETC´s) play an important role in the development of metastases in breast cancer patients and are therefore suitable as a target for improving current therapeutic approaches (which are adjuvant therapies in the form of chemotherapy, radiation therapy and hormone therapy).
 
Process / Method
We have developed a non-specific magnetic separation process (without antibodies) for the depletion of CETC´s from peripheral blood. The fundamentals of the method is an approach¹, which is based on the selective interaction between tumor cells / healthy cells (leukocytes) and magnetic nanoparticles (magnetite) coated with carboxymethyldextran (CMD).
Under defined conditions (e.g. incubation time, plasma addition) tumor cells show a more intensive interaction (endocytosis) with CMD nanoparticles, and therefore can be separated from the bigger part of healthy cells by using a magnetic separation process.
Aiming at the return of healthy cells (leukocytes) to the patients (preservation of the immune system of the patients), we have further developed the above mentioned method into a flow method with gentle magnetic separation. In this process, CMD-coated magnetite-based nanoparticles with a core diameter of 25 nm are used, which allow separation using the low-gradient method with an external separation column (blood bag).
This procedure was verified using patient blood. The safety of the procedure was proven in an animal study (dogs).
 
Objective
The stage of development of the method offers a high potential for cancer treatment in the field of adjuvant therapy. Clinical studies are necessary for the clinical implementation (Fig. 1) and approval.
 
¹Clement, J.H. et al., Cancer Res. Clin. Oncol. 132 (2006) 287-292